Image projector display device

ABSTRACT

An image projector display device projecting an image onto a surface substantially parallel to a path of light emitted through a representation of an image and a projection/objective lens. The display device compensates for the varying distances of the surface onto to which the image is projected from the projection/objective lens to display a clear, non-distorted image.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a U.S. continuation patent application of,and claims priority under 35 U.S.C. §120 to, U.S. patent applicationSer. No. 11/850,912, filed on Sep. 6, 2007, now U.S. Pat. No. 7,478,912on Jan. 20, 2008, which '912 application published as U.S. patentapplication publication 2008/0024734, and which '912 application is aU.S. continuation patent application of, and claims priority under §120to, U.S. patent application Ser. No. 11/209,837, filed on Aug. 24, 2005,now U.S. Pat. No. 7,267,444, and which '837 application is anonprovisional application of, and claims priority under 35 U.S.C.§119(e) to, U.S. provisional patent application 60/604,495, filed onAug. 26, 2004.

The disclosure of each of the above mentioned U.S. patent applications,any and all publications thereof, and patents is hereby incorporatedherein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention generally relates to projecting an image onto a surfacethat is substantially parallel to an axis of light passing through anobjective lens, and more particularly to projecting an image from animage representation onto a surface where the angle from one portion ofthe image representation to the surface is different than the angle fromat least one other portion of the image representation.

2. Description of Related Art

A typical image projector will shine a light source towards an imagerepresentation, such as a slide or transparency. The light then passesthrough an objective lens that will magnify the image representation todisplay an image on a surface.

A well-known image projector currently available is a slide projector.An optical path for a typical slide projector is shown in FIG. 1.

Normally, a slide projector comprises a light source 101 that projectslight towards a slide 109 that includes a representation of an image.The light source 101 may have a reflective mirror (not shown) to reflectscattered light back towards the slide, and a lens 105 may be interposedbetween the light source 101 and the slide 109 to further concentratelight onto the slide. While a condenser lens is shown, a no-sphere(planoconvex) lens could also be used for this purpose. The light beamthen passes through a projection/objective lens 115 that magnifies theimage and projects it for display onto a surface 120, like a screen orwall. A field lens (not shown) could also be provided that furtherfocuses the entire light beam passing through the slide 109 onto theobjective lens 115. The light source 101, slide 105, and objective lens115 are aligned along a common axis of light. This axis is substantiallyperpendicular to the surface 120 onto which the image is projected.

Another type of well-known projector is an overhead projector (notshown). Generally, the transparency is substantially perpendicular tothe projected image. The light source will shine up through an imagerepresentation, which is normally referred to as a transparency, to ahousing containing the lenses for projecting the image. The overheadlens housing will include some kind of condenser lens, normally afresnel lens, to collect light shined through the transparency anddirect it to a pupil of an objective lens. The objective lens thenprojects the image much in the sane way as the objective lens in theslide projector. A mirror is then used to redirect the image projectedfrom the objective lens so that the final projected image can bedisplayed on the surface, which is substantially perpendicular to thetransparency. But like a slide projector, the plane of the surface issubstantially perpendicular to the direction of light projecting theimage from the overhead projector.

In both the slide projector and the overhead projector, the projectedimage can be easily focused because the distance from the objective lensto the surface is substantially similar for the entire projected image.Therefore, the entire projected image can be at a substantially similardistance from a focal point of the objective lens.

The arrangement of either the slide projector or the overhead projector,however, would not be suitable for projecting an image onto a surfacethat is substantially parallel to the direction of light projected todisplay an image. Some portions of the projected image would be muchcloser to the objective lens, while other portions would be much furtherfrom the objective lens. This would distort the image so that the imageprojection portions closer to the objective lens would appear shortened,and the portions further from the objective lens would appear elongated.As a result, the projectors described above would display the image on asubstantially parallel surface with a “fun-house” mirror like effect.

To properly display an image on the substantially parallel surface, adisplay device like an image projector must account for the varyingdistances throughout the image projection from the projection/objectivelens.

SUMMARY OF THE INVENTION

The invention avoids the disadvantages and drawbacks of the related artby allowing a proper display of an image.

The invention thus provides a device for projecting an image onto asurface that is substantially parallel to an axis of the light passingthrough the objective lens.

According to an aspect of the invention, a device for displaying animage includes a light source, an image representation disposed in apath of light emitted from the light source, and an objective lensdisposed proximate the image representation to project an imageprojection onto a surface substantially parallel to the path of lightemitted from the light source through the image representation and theobjective lens, wherein the image projection is substantially similar tothe image.

The device may further include a reflection mirror reflecting lightemitted from said light source toward the image representation. Thedevice may also include a planoconvex lens disposed between said lightsource and the image representation, and adjacent to the imagerepresentation. In addition, a fresnel lens may be disposed between theimage representation and the objective lens. The light source may be alight emitting diode. The distance from the light source to a center ofthe objective lens is at a range of about 75 mm and about 225 mm. Theimage representation may be a distorted representation of the image, orthe image representation may be substantially similar to the image. Theimage projection may be at least about 15 times greater in size thansaid image representation. An angle between an axis of light projectedfrom a center of the objective lens and the surface may be less thanabout 10 degrees.

According to another aspect of the invention, a device for displaying animage includes a means for emitting light, such as a light bulb, LED orthe like, a means for representing the image, such as an imagerepresentation slide, disposed in a path of light emitted from the lightemitting means, and a means for projecting the image, such as an objectlens, disposed proximate the image representation means to project animage projection onto a surface substantially parallel to the path oflight emitted from the light emitting means through said imagerepresentation means and said image projecting means, wherein the imageprojection is substantially similar to the image.

The device may also include a means for projecting light, such as areflection mirror or a condenser lens, from said light emitting meanstowards said image representation means. The device may also include ameans for diffracting light, such as a fresnel lens, to orient an angleof light incident to said image projecting means. The device may alsoinclude a means for concentrating light, such as a condenser lens,projected from said light projecting means towards said imagerepresentation means. In addition, the distance from the light emittingmeans to a center of the image projecting means is at a range of about75 mm and about 225 mm. The projected image may be about 15 timesgreater in size than said image representation means. Further, an anglebetween an axis of light projected from a center of said imageprojecting means and the surface is less than about 10 degrees.

A further aspect of the invention provides a night light for displayingan image including a light emitting diode (LED), a representation of theimage disposed in a path of light emitted from the LED, an objectivelens disposed proximate the representation of the image to project aprojected image onto a surface substantially parallel to the path oflight emitted from the LED through the representation of the image andthe objective lens, and an orientation lens that orients an angle oflight incident to the objective lens, wherein the projected issubstantially similar to the image.

The night light may also include a reflection mirror reflecting lightfrom the LED toward the representation of the image and a concentrationlens that concentrates light from the LED onto the representation of theimage. The night light may further include a condensing lens disposedbetween the LED and the representation of the image.

Additional features, advantages and embodiments of the invention may beset forth or apparent from consideration of the following detaileddescription, drawings, and claims. Moreover, it is to be understood thatboth the foregoing summary of the invention and the following detaileddescription are exemplary and intended to provide further explanationwithout limiting the scope of the invention as claimed. For example,while the invention was developed to solve certain problems in nightlight displays, it may be used in other applications and with otherdevices where an image display is desirable.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention, are incorporated in and constitute apart of this specification, illustrate embodiments of the invention, andtogether with the detailed description serve to explain principles ofthe invention. No attempt is made to show structural details of theinvention in more detail than may be necessary for a fundamentalunderstanding of the invention and the various ways in which it may bepracticed. In the drawings:

FIG. 1 illustrates an optical path of typical slide projector;

FIG. 2 illustrates a front elevational view of an image display deviceaccording to principles of the invention;

FIG. 3 illustrates a side elevational view of an optical path for animage display device according to an embodiment of the invention;

FIG. 4 illustrates a representative view of an angle between theprojection surface and an objective lens according to an embodiment ofthe invention; and

FIG. 5 illustrates a side elevational view of an optical path for animage display device according to another embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The embodiments of the invention and the various features andadvantageous details thereof are explained more fully with reference tothe non-limiting embodiments and examples that are described and/orillustrated in the accompanying drawings and detailed in the followingdescription. It should be noted that the features illustrated in thedrawings are not necessarily drawn to scale, and features of oneembodiment may be employed with other embodiments as the skilled artisanwould recognize, even if not explicitly stated herein. Descriptions ofwell-known components and processing techniques may be omitted so as tonot unnecessarily obscure the embodiments of the invention. The examplesused herein are intended merely to facilitate an understanding of waysin which the invention may be practiced and to further enable those ofskill in the art to practice the embodiments of the invention.Accordingly, the examples and embodiments herein should not be construedas limiting the scope of the invention, which is defined solely by theappended claims and applicable law. Moreover, it is noted that likereference numerals represent similar parts throughout the several viewsof the drawings.

The invention discloses an image display device that displays an imageonto a surface that is substantially parallel to the direction of lightpassing through a representation of an image and theprojection/objective lens. Examples of such devices include, but are notlimited to, night lights, floor or desktop mounted displays,advertisement displays, and the like.

FIG. 2 shows an image projector according to principles of the presentinvention. The display device 200 can be plugged into a standardelectrical socket 201 to upwardly project an image 209 along a wallproximate the display device. Other types of power supplies, such as oneor more batteries, may also be used. While the drawing shows an upwardlyprojected image, the invention can be used to project the image alongthe wall and/or ceiling in any direction. Moreover, the invention mayprovide a single display device that can project the image in varyingdirections.

The display device 200 may be capable of projecting an image from asingle, fixed image representation of an image, like a slide.Alternatively, the representation of the image can be removable so thatany number of images could be displayed by a single display device bysimply changing the slide. The images projected by the display device200 may be of, for example, any theme or figure related to sports,vehicles, cartoons, movies, politics, nature, holiday, fantasy, art,music, science fiction, and locations.

According to an embodiment of the invention, multiple slides may be usedand alternated so that the projected image changes. By way of oneexample, a slide may include a digital memory that holds one or moredigital images. Images from the memory are displayed within the slide,such as in a manner similar to computer implemented projectors. Theslide has a processor for automatically changing the images displayed onthe slide, thereby changing the images projected. The slide may have aninput to enable a user to upload images, such as from a digital cameraor computer, thereby allowing customization of the image or images to beprojected.

The display device 200 may have a decorative housing 205. Here, thehousing 205 is a stock racing car projecting the image 209 of acelebrating driver through its windshield. Other embodiments may also beused.

The housing 205 may be designed to relate to the image and/or imagesprojected. For example, the display shell may have a design related to,for example, any sports theme, vehicle theme, cartoon theme, movietheme, political theme, nature theme, holiday theme, fantasy theme, arttheme, music theme, science fiction theme, and location theme. Thehousing 205 may be fabricated from any material suitable for aprojection display device such as plastic, ceramic, metal, or glass. Thehousing 205 may also be adapted in any suitable manner to allow light topass through a portion thereof to permit the projection of an image.

The display device 200 illustrated in FIG. 2 has a night light structurethat is plugged directly into the socket. According to an embodiment ofthe invention, a separate display device may be provided using a desklamp type structure that can be powered, for example, by a battery orvia an electrical cord. The housing 205 can also be adapted to letanother electrical device to be plugged into display device 200.

Now an optical path of the display device according to an embodiment ofthe invention will be described. As can be seen in FIG. 3, optical path300 includes a light source 301 that shines a light towards therepresentation of the image or slide 309. Because the light emitted fromthe light source 301 scatters in all directions, a reflection mirror 303may be provided to reflect scattered light back towards the slide. Anylight source can be used, including, but not limited to, an incandescentbulb, a fluorescent bulb, a neon (i.e., inert gas) bulb, a halogen bulb,and a light emitting diode (“LED”). The electrical components provided,such as one or more ballasts, will depend on the type of light sourceselected, as is well-known by those persons having ordinary skill in theart. An LED may be advantageous, however, because of its low powerconsumption, low heat emission, and high luminance properties ascompared to other types of light sources.

Another lens, such as lens 305, can be interposed between the lightsource 301 and slide 309 to concentrate light onto to the slide. Thislens may be an optical lens, such as a planoconvex lens. The lightpasses through slide 309 and strikes a fresnel lens 313 at an angle withrespect to the slide 309. The angle can be anywhere from about zero (0)degrees to ten (10) degrees but an angle of about zero (0) degrees isshown. The fresnel lens 313 changes the direction of light and focusesit towards the projection/objective lens 315. The objective lens 315 hasa surface, which may be asymmetrical, and can be at an angle of aboutzero (0) degrees to about twenty (20) degrees, but an angle of about ten(10) degrees is shown. Ideally, the fresnel lens 313 is disposed atsubstantially the same angle as the objective lens 315. Light thenpasses through the objective lens 315 where the image is projected ontothe substantially parallel surface.

According to an embodiment of the present invention, the distance fromthe light source 301 to the center of objective lens 315 is in the rangeof about 75 mm and about 225 mm, more specifically in the range of about112.5 mm and about 187.5 mm, and more specifically about 150 mm. But anydistance may be suitable depending on, for example, the desired size ofthe image projection, the size of the slide, or the focal length of theobjective lens. According to an embodiment of the invention, theprojected image may be at least about 15 times larger than the imagerepresentation, and more specifically the projected image may be atleast about 30 times larger than the image representation.

Accordingly, the optical path 300 accommodates the vary distances of theportion of a surface onto which the image is projected by angling a pathof light projecting from the objective lens 315 to display an image.Such an arrangement eliminates the “fun-house”mirror effect distortionand permits display of a substantially focused image.

FIG. 4 illustrates an angle a of the common optical axis 317 of theslide 309 and objective lens 315 in relation to the surface 320 uponwhich the image 330 is projected.

Because the display device of the invention can be used as a night lightproximate the wall 320, the display device must be able to project asubstantially clear image at a highly acute, tight angle that issubstantially parallel to the surface. Here, the angle .alpha. is shownto be about 5.7 degrees, but the display device of the invention issuitable for projecting the image 330 when the angle between the commonoptical axis 317 and the surface 320 is at other angles, such as lessthan about 10 degrees.

Now an optical path of the display device according to anotherembodiment of the invention will be described. Looking at FIG. 5,optical path 400, includes a light source 401 projecting light towards acondenser lens 405 that collects emitted light. The light collected bythe condenser lens 405 then passes through a light adjusting lens 406that concentrates light on the slide 409. The light beam passing throughthe slide 409 then passes through a grating lens 413. The gratingincluded on lens 413 diffracts the light so that it strikesprojection/objective lens 415 at an angle. This angle may be about zero(0) degrees to about ten (10) degrees but an angle of about zero (0)degrees is shown. The grating diffracts the light at a number of anglesaccounting for the varying distances of the surface portions onto whichthe image is projected. Light then passes through the objective lens 415to project the image onto the substantially parallel surface 420.

While the invention has been described in terms of particularembodiments, those skilled in the art will recognize that the inventioncan be practiced with modifications in the spirit and scope of theappended claims. These examples given above are merely illustrative andare not meant to be an exhaustive list of all possible designs,embodiments, applications, or modifications of the invention.

1. An image display device for displaying an image on a surface, comprising: a housing configured to be located proximate to the surface; a light source arranged on said housing; an image representation disposed in a path of light emitted from said light source, wherein said image representation is a distorted representation of the image; and an objective lens disposed proximate said image representation to project an image projection onto a surface substantially parallel to the path of light emitted from said light source through said image representation and said objective lens.
 2. The image display device of claim 1, wherein a distance from said light source to a center of said objective lens is at a range of about 75 mm and about 225 mm.
 3. The image display device of claim 1, further comprising a reflection mirror reflecting light emitted from said light source toward said image representation.
 4. The image display device of claim 3, further comprising a planoconvex lens disposed between said light source and said image representation.
 5. The image display device of claim 4, wherein said planoconvex lens is adjacent to said image representation.
 6. The image display device of claim 4, further comprising a fresnel lens disposed between said image representation and said objective lens.
 7. The image display device of claim 1, wherein said image representation is substantially similar to the image.
 8. The image display device of claim 1, wherein the image projection is at least about 15 times greater in size than said image representation.
 9. The image display device of claim 1, wherein said objective is arranged so that an angle between an axis of the path of light projected from a center of said objective lens and the surface is less than about 10 degrees.
 10. The image display device of claim 1, wherein the surface is a wall, and wherein said housing attaches to the wall via an electrical outlet.
 11. An image display device for displaying an image on a surface, comprising: a light source for emitting light; means for mounting said light source proximate the surface; means for representing the image disposed in a path of light emitted from said light source; means for concentrating light projected from said light projecting means towards said image representation means and a means for projecting the image disposed proximate said image representation means to project an image projection onto a surface substantially parallel to the path of light emitted from said light source through said image representation means and said image projecting means, wherein the image projection is substantially similar to the image
 12. The image display device of claim 11, wherein a distance from said light source to a center of said image projecting means is at a range of about 75 mm and about 225 mm.
 13. The image display device of claim 12, further comprising a means for projecting light from said light source towards said image representation means.
 14. The image display device of claim 12, wherein the projected image is about 15 times greater in size than said image representation means.
 15. The image display device of claim 12, wherein an angle between an axis of the path of light projected from a center of said image projecting means and the surface is less than about 10 degrees.
 16. The image display device of claim 11, wherein the surface is a wall, and wherein said means for mounting attaches to the wall via an electrical outlet.
 17. A night light for displaying an image on a surface, comprising: a housing configured to be located proximate to the surface; a light source; a representation of the image disposed in a path of light emitted from said light source; and a reflection minor reflecting light from said light source toward said representation of the image; a concentration lens that concentrates light from said light source onto said representation of the image; a condensing lens disposed between said light source and said representation of the image; and an objective lens disposed proximate said representation of the image to project a projected image onto a surface substantially parallel to the path of light emitted from said light source through said representation of the image and said objective lens; and an orientation lens that orients an angle of light incident to the objective lens.
 18. The night light of claim 17, wherein said surface is a wall, and wherein said housing attaches to the wall via an electrical outlet.
 19. The night light of claim 17, wherein an angle between an axis of the path of light projected from a center of said image projecting means and the surface is less than about 10 degrees.
 20. The night light of claim 17, wherein the light source is a light bulb or an LED. 